In the construction of a home or building, it is usual practice to provide a T-fitting wherever a fixture of the type having a trap is to be located. The T-fitting connects a soil pipe and a vent pipe and is provided with a center port to which the trap of the fixture is connected, all as is well known in the art. In the case of a lavatory or the like, this connection is made through an appropriate hole in the wall behind which the T-fitting is located and in front of which the lavatory is mounted.
In a typical 2 1/2 bath home there will usually be 10 or more T-fittings for connection to the traps of one or more lavatories, one or more showers, one or more bathtubs, a kitchen sink, a washing machine drain, and the like.
In the plumbing industry today, it is common to make piping such as soil pipe and vent pipe, and fittings such as T-fittings, traps, and the like out of plastic material. The most commonly used plastic material for such applications is acrylonitrile-butadiene-styrene (ABS) or polyvinylchloride (PVC). The present invention will be described in its application to plastic piping and fittings, but is not necessarily so limited.
It is usual practice, during construction, to install the basic plumbing well before installation of the various fixtures. As a consequence, the intermediate ports of the T-fittings will not have traps connected thereto for some time. It is therefore desirable to close and seal the intermediate ports of the T-fittings to prevent clogging of the basic plumbing with dirt and foreign material which might inadvertently enter the intermediate T-fitting ports during construction. In addition, during plumbing construction, it is frequently desirable or required to perform air tests or water tests to assure that the various joints are properly connected and are fluid-tight.
The closing and sealing of the intermediate ports of the T-fittings has been accomplished by the prior art in a number of different ways. One common approach is to insert a length of pipe through the hole in the wall and into the intermediate port of the T-fitting, permanently adhering the pipe to the intermediate port by gluing, solvent welding or the like. This provides a fluid-tight connection. This pipe will ultimately serve as a trap bushing when its respective fixture is ultimately installed. The free end of the pipe is closed by a wafer cap. The wafer cap comprises a relatively thin plastic cap, solvent, welded or otherwise sealingly affixed to the free end of the pipe. The necessary cleaning and welding steps are time consuming. Furthermore, while the air or water tests are performed at relatively low pressures, the wafer caps are characterized by a relatively high failure rate of from about 30% to about 35%.
Another prior art approach is to apply to the free end of the pipe or trap bushing affixed to the center port of the T-fitting, a resilient rubber cap held in place by a hose clamp. Unlike the wafer cap, this type of closure has the advantage of being reusable. Nevertheless, its installation is time consuming, it is frequently lost or misplaced, and it, too, demonstrates a relatively high failure rate.
Today most basic plumbing of the type to which the present invention is directed is accomplished with so-called "schedule 40" pipe and pipe fittings. Pipe and fittings of this type are conventional, readily available, and well known in the art. The term "schedule 40" refers to the thickness or gauge of the pipe wall. Schedule 40 pipe and its fittings come in several sizes, as is well known in the art.
Yet another approach by prior art workers is to close the free end of the trap bushing or pipe extending from the center port of the T-fitting and through the wall by a schedule 40 cap. This is a relatively heavy-duty cap structure which is glued or solvent welded to the free end of the pipe. The cap is expensive, must ultimately be removed, and constitutes a single use item.
The present invention relates to a test closure plug which, in combination with a conventional adapter and adapter nut, can be used to close and seal the free end of the pipe or trap bushing attached and sealed to the intermediate port of the T-fitting. The test closure plug of the present invention overcomes the problems associated with the various prior art devices for this purpose. Once installed, the test closure plug of the present invention will easily withstand a head of water or a water test or air test. When it is time to install the fixture, the test closure plug can be removed from the pipe or trap bushing and the adapter thereon by removal of the adapter nut. The adapter, the adapter nut and the adapter washer (whether it be a separate washer or an integral part of the nut) can be used to connect the trap to the trap bushing by a slip joint, well known in the art. The test closure plug can be reused again and again. The plug is characterized by excellent strength and is easy and inexpensive to manufacture. It will be apparent that the test closure plug of the present invention provides a closing and sealing device for the intermediate port of the T-fitting which is both reliable, safe and easily installed.